1. Technical Field
The present invention relates to a cleaning device having a cleaning roller which cleans a charging roller which charges an image carrier, and to an image forming device, such as a copier or a printer or the like, which employs an electrophotographic method and is equipped with the cleaning device.
2. Related Art
Devices utilizing corona discharge development, such as scorotron chargers, have often been used as charging devices of image forming devices such as copiers or printers or the like which employ an electrophotographic method. In contrast, the contact-charging method, which carries out charging of an image carrier by causing a conductive charging roller to directly contact an image carrier, has become the mainstream method recently because the power source efficiency thereof as well is good.
In such a contact-charging method charging device, there is the problem that, because the charging roller is always contacting the image carrier, it is easy for contamination to arise due to foreign matter adhering to the surface of the charging roller. At the downstream side of the transfer process, the surface of an image carrier on which the image forming operation is repeatedly carried out undergoes a cleaning process which removes foreign matter such as residual toner and the like after the transfer, and thereafter enters into the area of the charging process. However, even after going through the cleaning process, minute particles which are smaller than the toner, such as portions of the toner or external additives of the toner or the like, remain on the image carrier without being cleaned, and adhere to the surface of the charging roller. The foreign matter adhering to the surface of the charging roller causes non-uniformity in the surface resistance value of the charging roller, and abnormal discharging or unstable discharging occurs, and the uniformity of charging deteriorates.